Decorative chippings straight onto rubble?

Hi all....

I have a couple of terraced areas in the garden. Each approx. 4 m x 4 m. Both are dug out ready for paving, to a depth of approx. 150 mm.

Need to get a useable space quickly so the plan is to fill with decorative stone chippings.

One terrace is soil and clay, the other is at least 300 mm depth of rubble (crushed concrete, bricks, old mortar etc.).

On both terraces, to save cost of stone I intend to raise the level by filling back in with free rubble off gumtree, then top with a couple of inches of stone.

Question is, given the large amount of rock, rubble, concrete, brick etc. in the base; do I need to use a weed membrane under the dec. stone? Or under the rubble infill for that matter?

6 inch depth of crushed building materials and stone chippings is hardly a very inhabitable environment for weeds to grow, right?

Thoughts please?

A deep infill of rubble will take a long time to fully settle, there will be air gaps scattered through it for many years, so allow for regular infill until it fully stabilises.

Are you referring to the rubble infill that I intend to do as "deep infill"? Or are you referring to the 300 mm rubble that's already in place? (This has been in for 10 yrs)

Edit: I see what you mean, may need to be topped up.

Any thoughts on the need for a membrane anyone?

Yes on top of rubble.Certain weeds will grow anywhere and once they germinate will send roots down through rubble. At least if you get things like sycamore seeds germinating in the decorative chippings they are easily pulled up.